It’s been said that with enough soap, one could blow up just about anything. A more modern interpretation of this thought is that with enough knowledge of chemistry, anything is possible. To that end, [Peter] has certainly been doing a good job of putting his knowledge to good use. He recently worked out a relatively inexpensive and easy way to etch metals using some chemistry skill and a little bit of electricity.
After preparing a set of stencils and cleaning the metal work surface, [Peter] sets his work piece in a salt solution. A metal bar is inserted in the other end of the bath, and both it and the work piece are connected to electrodes. The flow of electricity removes some metal from the exposed work surfaces, producing whatever patterns [Peter] wants.
One interesting thing that [Peter] found is that the voltage must stay under 6 volts. This is probably part of the reason it’s relatively easy to etch with even a wall wort. Above that, the iron work piece produces a different ion which can clog the work surface and create undesirable effects. Additionally, since his first experiments with this process he has upgraded the salt bath with magnetic stirrers. He also gets the best results in a very cold environment.
There are many other uses for etching metals, too. Creating your own printed circuit boards comes to mind, but there are plenty of other uses as well. What will you do with this technique?
25 thoughts on “Etching Your Own Metal”
For proper etching in steel or iron one should use solution of ferrous sulphate (FeSO4x7H2O) or ammonium chloride (NH4Cl) as electrolyte. I don’t know exact proportions, so experimentation is needed. Traditionally etching in metals was done using nitric acid: https://en.wikipedia.org/wiki/Aquatint
“wall wart”. Wort is the liquid extracted from the mashing process during the brewing of beer or whisky.
…ahh sweet nectar!!
Only issue with using stainless steel is it produces chromium in the electrolysis process so I guess it would here too.
Perhaps you can combine with the rust removal process and colour it whilst processing parts at the same time.
Yeah, don’t etch stainless steel using this method, you can evolve poisonous chromium compounds. Also don’t use stainless plates for electrolytic rust removal for the same reason. That said, the amounts described here are probably not super dangerous.
This will make hex and indeed it is nasty stuff for the environment, but you can knock it down with some sodium dithionite, and that then can be disposed of safely.
Sure, let me just head down to Wal-Mart and pick up some of that…
It’s not that hard to get, and not that expensive for technical grade
Does the hardness of the metal have any impact ?
As in, would you be able to etch a press (for coins example) with this method over a longer time ?
I wouldn’t imagine so. Hardness and toughness of metals is usually a physical property and not a chemical one.
Well yes and no. Hardness in steels is a function of grain structure and that can impact how chemically active the surface can be.
So the best result was achieved with saturated saline solution, 5V @ 1A.. Can this be done with a regular 1A USB charger?
as long as your charger was current limited somehow (besides an internal fuse of course)
Processes like electroplating and electroetching should be controlled by measuring amperage, not voltage.
Both are relevant as you’re using electricity to force a reaction to go a certain direction. Voltage does matter but you’ve got considerable wiggle room (Check out a Pourbaix diagram for more info). Amperage’s precision requirement depends on surface area if you want to do things optimally and not boil away your electrolyte.
I worked in this industry for over forty years and these processes were universally worked by amperage. Mostly because large working solutions tend to change over time, temperature and the volume of work passing through them during a shift. The only thing that one could use to keep results within spec was to work with current density. Voltages, as long as they were higher than the minimum to get the reaction going in the right direction, was never a real concern simply because they would vary widely over time.
Having said that, there are some processes like anodizing and alloy plating where voltage is a significant factor, but on the etch and basic plating lines, everyone works with amperage.
Really? He.. “Worked it out”. This has been done for well over a century with various chemicals for different materials and final finishes etc. So very not worthy of a post on here. Especially since there are also 34,527,164,839 other examples of this on the web already.
Please stop regurgitating the same ole stuff. It causes stagnation.
A wild pedant appeared!
Do you know what happens if you use the century old formulas? Suddenly you’re getting creeped by the EPA, NSA and FDA.
Not at all. It’s not the solutions that you use, it’s how you handle the wastes that are the issue. Some modern formulations claim to be better in that regard, but often that’s not always the case. There is no quick fix to replace good shop practice.
Yea, nothing. In fact, simple sodium chloride solution is all that is required for most metals. It may not be the best solution , or give the finish you want , but it will do just fine.
This article is somewhat confusing. It mentions an iron work piece, but the linked gallery pertains to X5CrNi18-10 (stainless steel). There’s a reference to magnetic stirrers, but I can’t find that in any of the linked content. Was the article based on information from the tip line rather than the content? Is something missing?
I’ve tried etching stainless steel in a saltwater electrolyte, using 12V at several amps, with very different results. There was no relief, but the etched surface had a crystalline appearance as if certain elements of the alloy were removed along grain boundaries. Very strange. Since then I’ve just used good ol’ ferric chloride, which performs as expected.
Myth Busters had a great use for this technology. Dissolving bars in a jail cell. :)
I’m a high school science teacher and I just did something like this last week with the student-led chemistry club. We used 9V batteries, alligator leads, and Q-tips dipped in a salt-vinegar solution. Some masked designs off with masking tape and hobby knives, while some painted freehand with the Q-tip. Very fun!
What did you etch? got a link to pics? My wife is a high school chem teacher, and I bet she’d love that.
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